Water Recycling Criteria for Agricultural Irrigation
The 2012 report, “Review of California’s Water Recycling Criteria for Agricultural Irrigation,” was developed in response to increased interest in expanding the amount of recycled water used for agricultural purposes.
- It specifically addressed the risk of exposure and infection from waterborne pathogens, such as Cryptosporidium and E. coli, due to the irrigation of a wide variety of food crops using recycled water.
Key issues addressed include:
- Characterizing “safe” recycled water for use in irrigation.
- Appropriate assumptions regarding an acceptable risk to public health.
- Relevancy of current criteria for reducing viruses and using chlorine disinfection.
- Need for a “multiple barrier” of treatment processes to remove microorganisms.
- Use of turbidity as a valid parameter to assess the performance of treatment processes.
- Standards used to clarify and define “secondary wastewater treatment,” which involves biological treatment processes to remove contaminants and/or bacteria.
- Use of total coliform bacteria to assess the effectiveness of disinfection in reducing microorganisms.
- Ability of crops to take in viruses through their root systems, leaves, and other points of entry, and any associated risks to public health.